$ { {-4} \times \left[\begin{array}{rrr}{-1} & {1} & {4} \\ {2} & {4} & {0}\end{array}\right] = {?} } $
Solution: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{-4}\times{-1} & {-4}\times{1} & {-4}\times{4} \\ {-4}\times{2} & {-4}\times{4} & {-4}\times{0}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{4} & {-4} & {-16} \\ {-8} & {-16} & {0}\end{array}\right]}$